Intrusive medical devices such as central venous catheters (CVCs), urinary catheters and endotracheal catheters may introduce infection into hospitalized patients when used since the devices are subject to microbial colonization. The most common source for catheter colonization is the patient's skin, whereby organisms migrate from the skin along the intercutaneous catheter segment and ultimately enter the bloodstream and can create serious infections.
The most common organisms causing these infectious complications are Staphylococcus epiderimidis and Staphylococcus aureus. In the case of vascular catheters, these two organisms account for almost 70-80% of all infectious organisms, with Staphylococcus epidermidis being the most common organism. Candida albicans, a fungal agent, account for about 10-15% of catheter infections. A number of studies have revealed that organisms such as Staphylococcus epidermidis send projections into small defects in the polypropylene material, which is used in catheters. Protection against infection is particularly desirable at or around the catheter insertion point to limit entrance of organisms into the intercutaneous tunnel.
A second area in which antimicrobial measures are desirable is that of the catheter's proximal hub through which fluids enter or exit the catheter. The hub may be vulnerable to hub-related luminal and skin-related extraluminal colonization. Although the hub is normally sealed against infection to some degree by mechanical means, such as a cap or other fitting, infectious microbes may enter the catheter when this fitting is removed. Further, if the cap is fitted poorly, microbes may migrate across the intended seal. It is estimated that up to 20% of catheter-related infections begin around the catheter hub.